Safety latch for elevators



Sept. 4, 1951 I w. w. WILSON 2,567,044

SAFETY LATCH FOR ELEVATORS Filed Aug. 9, 1946 2 Sheets-Sheet 1 INVENTOR. WILL/AM WEBSTER WILSON p 4, 1951 w. w. WILSON 2,567,044

SAFETY LATCH F'OR ELEVATORS Filed Aug. '9, 1946 2 Sheets-Sheet 2 {I 3/.I in Y 32 pl y i 34 ATTORNEY patented Sept. 4, i951 UNITED {STATESPATENT o- I E SAFETY "LATCH FOR ELEVATORS William Webster .Wilson, LosAngeles, Calif. pplication August 9, 1946, Serial No. 689,496

3fllaims. :1 -This inventionrelates t elevators employed insuspending'members such as pipes or tubes in derricks and relates inparticular to an improved latch for elevators.

"It-is an object of the invention to provide a center latchelevatorhavinga rugged and effective latch :anda simple lock forpreventingina'dvertent opening of the latch. My present-invention isshownjn conjunction with a center latch elevator of the characterdescribed in llnited states Patent No. 2,356,805, granted tome Au ust:29, 1944.

;It isian object'of the inventicnto provide a egmbined latch and lockfor pi pe elevators hav" ine-ars n e 'n a s o ope ation.

j-Itlis an object of the invention to provide an elevator latch of thecharacter set forth in the preceding 1 paragraph having a latch leveradapted ftoengage alatch lug and a lock lever mountedon the latch leverfor engagement with a lock lug, this look lever having a manually nageable portion .by which the release of the lpckand, the release ofthelatch is accomplished.

.A further object vof the invention is to provide in alatch and lockcombination of this character a simple cooperation of elements whereinthe Wall which supports'the'lock lug serves as a guard for the manuallyengageablehandle of the'lock lever- Further objects and advantages ofthe invention willbebrought out in the following part of thespecification, wherein reference to specific details of construction arefor the purpose of fully disclosing a preferred embodiment of theinvention without limiting the scope thereof set forth in 'the appendedclaims.

"Referring to the drawing, which is for trativejpurposes only,

"Fig. 1 is a planview of a preferred embodiment (if-my invention.

Fig. 2 is a front elevation corresponding to ig. 1.

Fig. 3 is a fragmentary sectional view, taken asindicated 'bythe line 33of Fig. 2.

Fig. 4 is an enlarged perspective view of the latch lever.

"Fig. '5 is a fragmentary isometric view showing the'operativerelationship of the latch lever, lock lever and lock lug.

The elevator shown in the drawing comprises apipe encircling structure 9adapted to be closed illusandlatched around a pipe which is to be sus"pended or lifted. Herein the term pipe is inclusive of any objectused'in a well derrick or in a well having a portionadapted to beenga'ged'by the elevator'whereby 'the'li'fting or suspension of suchmember is accomplished. 'In the form of the invention shown,the-elevatorccmpr-ises two cooperating parts H and I2 hinged together bymeans of a hinge pin M so 'asto be swingable from open position into theclosed position in which the elevator is shown. The-jaws 'H and I"? areformed with inner semi-cylindrical'boresurfaces l5 and I6, defining'anopening'to receive the cylindrical parts, such as a'pipe, which is to belifted or suspended. The jaws ll andlZ'hav'e respectivelyfirst'and'second free'en'dsl'l and i8 which are brought'irltojuxtaposition when the jaws are closedaround a pipe. The'first free'endI! has thereona latch lug '19 having a face or shoulder lying totheright of' the median plane (1-41 of the elevator and'being disposed on-a plane b-b which-crosses the plane a-a in the mannershown in Fig. 1.

The second free end ['8 has lugs 2|, 22, 23,and

24 projecting therefrom-to support "a hinge pin 25 on a vertical axiswhich is spaced from the hinge-pin M a greater distance than the centerof the face or shoulder 28- ofthe latch'lug l9. A latch lever '26 isswingable 'on the hinge pin 25. This latch'lever 2.6' has verticallyspaced horizon ta'l arms 21 and .28, theleftward ends of whichswing-upon'the hinge pin 2'5, 'and a vertical bar portion 29'whichconnects'the rightward ends-of the arms '21 and 28 and provides betweenthe arms 21 and 28 a latching shoulder 38 for engagement with thelatching shoulder 23 of the latch lug is. The leftward ends of the arms2:?

and 28 areconnected' by a vertical bar 3| and, for

rotating the latch lever 26 in counterclockwise direction, a spring 32'is placed around the intermediate'portion-of the pin 25, one end 33 ofthis sprin 32 engaging a'portion of the body or jaw l2, and the otherend 34 ofthe spring 32 engaging the bar 3! iofthe latch lever 26. Thespring 32 constantly urges the latch lever 26 into a position whereinthe latch face thereof will cooperate with the latch shoulder 20 of thelug Hi when the jaws II and 12 are in closed relation. A projection 34onthe'lug 23 of the jaw l2 limits the clockwise rotation of the latchlever 26.

As shown in Fig. 4, the latch lever 25'has vertically spaced lugs 36 and31 projecting from the frontfac thereof, these lllfs having openings toreceive a pin 39 on which a lock lever 18 is swingable. This lock lever40 is disposed near the rightward end of the latch'lever 2t and upon thefront face of the bar 29 thereof.

The lock lever 40- comprises a vertically elongated 'arcuate wall4'lwith'upper andlower'ends 3 of walls 42 and 43 projecting therefromtoward the latch lever 26 to engage the pin 39. These end walls 42 and43 are of the shape of circular segments, the radial edges of the topwall 42 being disposed at an angle of substantially 90 degrees and thelower end wall 43 having thereon a lug 44 to engage the bar 29 of thelatch lever 26 and thereby limit the counterclockwise rotation of thelock lever by a spring 45 which has its coiled portion surrounding thepin 39, this spring 45 being relatively weaker than the spring 34. Thelock lever 46 includes a fiat wall 41 which projects rightwardly fromthe arcuate wall 4| in substan--' tially parallel relation to the frontface of the bar 29 and in spaced relation thereto. This manuallyengageable portion 41 projects rightwardly beyond the rightward edge ofthe bar 29 so as to constitute a manually engageable handle which may bepulled forwardly as indicated by the arrow 48 of Fig. 3. A lockingshoulder 50 of the upper end wall 42 and that portion of the arcuatewall 4| adjacent thereto comprises a latch dog or shoulder proper forengaging a lock lug 5| formed on a wall 52 which projects from the .jawmember ll above the handle portion 41 of the lock lever 40 so as toserve as a guard for the handle portion 41 of the lock lever 40', aswell as for supporting the lock lug 5|.

From an inspection of Fig. 1, it will beperceived that the latch lever26 swings around a hinge pin 25 which is disposed with its axis at agreater distance from the axis of the hinge pin 14 than is the center ofthe face 20 of the latch lug l9. It is characteristic of thisarrangement of latch lever 26 and latch lug l9 that forces applied tothe jaws II and I2 tending to separate them will produce forces in thelatch lever 26 and latch lug l9 tending to prevent their disengagement.As an additional precaution against the latch lever 26 beinginadvertently rotated in clockwise direction around the hinge pin 25 soas to move the rightward portion ofv the latch lever 25 out ofengagement with the latch lug I9, the lock lever 49 and the lock lug 5|are provided.

When the latch mechanism is in operative condition, as shown in Fig. 1,the engagement of the lock lever 40 with the lock lug 5| preventsclockwise rotation of the latch lever 26. However, the lock lever 46 isso arranged with relation to the latch lever 26 that a single manual.operation will accomplish release of the lock lever 48 from engagementwith the lock lug 5| and clockwise rotation of the latch lever 26 so asto swing the same out of engagement with the latch lug l9. The workman,desiring to release the latch mechanism and open the elevator, reachesunder the guard wall 52 and pulls the lever portion 41 of the lock lever46 toward him. The force thereby applied to the lock lever 46 rotatesthe same in clockwise direction, against the force of the spring 45,into the position indicated by dotted lines 45a wherein the leftwardedge of the arcuate wall 4! engages the front face of the latch lever 26and the locking shoulder 59 of the lock lever 43 is moved leftwardly outof engagement with the lock lug 5|. Thereafter, the pull which theworkman exerts on the handle portion 4'! of the lock lever 40 acts uponthe latch lever 26 to swing the same in clockwise direction, therebycarrying the latching face 36 of the bar 29 out of engagement with thelatching face 20 of the latch lug l9, whereupon the jaws and i2 of theelevator will swing open.

When the elevator is in open position, counterclockwise rotation of thelatch lever 26 is limited by a shoulder 58 of the jaw l2, so that thelatch lever 26 is maintained in position for reengagement with the latchlug I9 when the elevator jaws i l and I2 are again swung into closedrelation. The swinging of the jaws II and I2 is accomplished by use ofhandles 60 and BI which project forwardly from the jaws II and I2 andhave knobs 62 and 63 thereon for manual engagement. The reengagement ofthe parts of the latch mechanism is accomplished merely by moving thejaws II and 12 into closed relation, for the reason that the latch lugI9 and the bar 29 of the latch lever 25 have respectively angularlydisposed faces 64 and 65 so that the bar 29 will ride over the lug l9and then drop into latching position, whereupon the locking shoulder 59of the lock lug 40 will move behind the lock lug 5 l One of the featuresof the latch and lock arrangement of the invention arises from the factthat the lock lever 40 projects forwardly from the latch lever, so thatthe latch lever 26 and the lock lever 4!) define vertical planes whichcross each other at, an angle of substantially This gives a cooperationof parts in the structure wherein inertia or momentum acting in thestructure in a direction-to cause release of the latch lever 26 will notproduce a release of the lock lever 49, and inertia or momentum actingin the structure in a direction to cause release of the lock lever 49will not have such direction as to cause release of the latch lever 26.In explanation of this, let it be presumed that inertia is actingforwardly or along the line a-a from the hinge pin 14 through the latchlever 26. This exertion of the force of inertia in the latch lever 26will tend to swing it in clockwise direction, but the same inertiaacting in the lock lever 49 will tend to hold it in locked position orat least will not move the lock lever 46 out of its locked position.Likewise, inertia acting leftwardly through the'center of gravity of thelock lever 46 so as to tend to swing the same in clockwise direction andunlock the same, will act longitudinally through the latch lever 26 andtherefore will exert substantially no opening force on the latch lever26.

I claim as my invention:

1. In a latch for an elevator comprising a pipe encircling structurewith first and second free ends adapted to be latched together when thestructure encircles the pipe, the combination of: a latch lug and a locklug respectively carried by said first free end, both of said lugs beingoutwardly spaced from their associated end of the structure, with thelock lug spaced a greater distance than the latch lug; a latch leverhinged on said second free end for engaging said latch lug when saidstructure encircles said pipe; spring means urging said latch leverintoa position for engagement with said latch lug; a lock lever on theouter face of said latch lever and positioned .so that when said latchlever is in latching engagement with said latch lug, said lock leverwill be positioned for locking engagement with said lock lug; means forurging said lock lever into engagement with said lock lug; manuallyengageable means carried by said lock lever for receiving a force whichwill swing said lock lever out of engagement with said lock lug" andsaid latch lever out of engagement with said latch lug; and a wallextending from said first free end in a position to guard said manuallyengageable means. 7

2. In a latch for an elevator comprising a pipe latch lever pivotallycarried by the other of said free ends for latchingly engaging the latchlug, when said structure encircles said pipe; means resiliently urgingsaid latch lever toward latching position; a fixed separate lock lugcarried by said one of said free ends positioned outwardly of said latchlug and beyond the latched position of said latch lever; a pivotallymounted "lock lever carried by said latch lever adjacent its free end:means resiliently urging said lock lever to a locking position betweenthe lock lug {and the latch lever upon movement of the latter to latchedposition, whereby forces tending to niove'the latch lever from latchedposition act to put the lock lever in compression; and manually operablemeans for actuating said lock lever to release position.

3. In a latch for an elevator comprising a pipe encircling structurewith first and second free ends adapted to be latched together when thestructure encircles the pipe, the combination of: a latch lug carried byone of said free ends; a latch lever pivotally carried by the other ofsaid free ends for latchingly engaging the latch lug, when saidstructure encircles said pipe;

means resiliently urging said latch lever toward 3 latching position; afixed separate lock lug carried by said one of said free ends positionedoutwardly of said latch lug and beyond the latched position of saidlatch lever; a lock lever having an elongate portion spanning the freeend of said latch lever and terminating in laterally projecting endlugs; means pivotally connecting said end lugs to adjacent parts of thelatch lever for pivotal swinging movement; means resiliently urging saidlock lever to a locking position between the lock lug and the latchlever upon movement of the latter to latched position, whereby forcestending to move the latch lever from latched position act to put thelock lever in compression; and a hand grip projection extending from theelongate portion of the lock lever in substantially parallel relation tothe front face of the latch lever, inwardly of the outer end of saidlock lug, for swinging said lock lever to release position.

WILLIAM WEBSTER WILSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,067,663 Grau Jan. 12, 19372,108,238 Strelow Feb. 15, 1938 2,356,805 Wilson Aug. 29, 1944

